Enrico Altavilla discovered a bug with how Google+ shows +1s for a page, which has already been patched by Google. It is pretty amazing and reminds me of how webmasters faked their PageRank back in 2005.
In short, by using a simple redirect on the page, a page was able to pretend it was another page and use the +1s from the page they are redirecting to as the their own +1s.
So when a site had a weird JavaScript redirect to YouTube, it thought the site was indeed YouTube and that page inherited the +1s YouTube had.
Again, this no longer works but I figured I share the story so if it happens again, a different way, we have something to look back at.
To learn more about this, see ideativi.it.
Forum discussion at Google+.
Update: +demetriosiragusa found this issue and supposedly the bug still works.
